Prep before recoat/tips to keep from repeat mistake

[nola mike]

Trying to repair a gash in my keel. Plan was 3 layers of 7" wide biax outside, and a layer inside (ski locker) if I felt inspired. Nothing structural on the inside. I had reinforced the keel years ago, but storm pounded it pretty good on a jetty. So ground/sanded the old repair.
I didn't get enough resin to account for screw ups. Layer #2 was up and looking good (upside down under trailer). I tried smoothing it one final time, and the whole thing fell on my non-Tyvek'd head/body (where the f are my suits?). So we're taking today and tomorrow off so that I can learn my lesson and wait for the PPE to come in, along with more resin.

1. Any way to support the glass from below? I don't recall having this problem last go round, but gravity's a b****.
2. What do I have to do to prep the one layer that I have up there? Poly resin, no wax. It will have sat for 72 hours before I can finish it.

 

[MikeSchinlaub]

Big upside down areas are some of the worst. Here are some tips.
1. I was taught that the cloth doesn't bons great by itself, and it should have csm underneath. Preferably 2 layers of mat to 1 cloth.

2. Don't saturate the glass so much. Use about 3/4 as much resin as you would if you were doing a flat horizontal area. It fell off because it weighed too much.

3. Roll the wet glass onto a paper towel tube, then roll it over the area. It will help tremendously in getting up there. Just make sure it is well stuck as you move on. It only takes a small area to start sagging and drag the whole piece down.

As for the surface prep, I can't answer that. I've only ever used resin with wax, so it always cures hard.

 

[froggy1150]

If you have a second set of hands... get some 10 mil plastic and some gaffers tape. Get the fabric up and rolled out then cover with the plastic and tape it up tight. I did a keel repair that way. I had it taped on one side, did the glass and then folded it up quickly. I was by myself. After it is mostly cured you can peel the plastic back and as long as you have no fixes to make just wipe with acetone to get the chemical process restarted. I had a couple air pockets I had to fix so I just ground out and had a mix of 1/4" chopped glass and cabosil that I filled the spots with and then did another layer

 

[froggy1150]

The layer you have up you probably will have to sand to get a mechanical bond. Corse grit like 32. If you wipe it with acetone and it gets tacky you will also have a partial chemical bond. Also I took small bites at my repair instead of fighting a bigger piece

 

[Scott Danforth]

BTDT with the patch falling on your head. then you need to take acetone to clean that off.....

agree with Mike, a bit less resin and roll it out. however I still have had issues

the plastic method works, unless there is a lot of carolina flare near the keel

i have taken a large garbage bag inflated by the exhaust of your shop vac and let that hold it up.

if the resin on the prior layer is still tacky, an acetone wipe should be all you need

if it kicked full-hard like it would down here in the florida heat, hit it with 40 grit and an acetone wipe.

 

[nola mike]

I like the idea of plastic +tape. I could tape one side, get the glass up there, tighten the plastic and then manipulate it through the plastic. I might cut the 46"strip into 2. Only a couple of inches for the hole, the rest is just keel protection. Also interesting about wetting out. I used a lot of resin on that piece so that I wouldn't have to add any once it was up. I'll be more judicious next time. It's been cooler the last few days. Ugh. Don't want to sand any more. Although I guess it won't take much